Smoke retardant vinyl chloride and vinylidene chloride polymer compositions

ABSTRACT

Smoke retardant vinyl chloride and vinylidene chloride polymer compositions are obtained by including therein a synergistic mixture of (A) at least one nickel compound selected from the group consisting of NiCO 3 , NiCrO 4 , NiI 2 , NiO, NiS, NiSO 4 , nickel acetylacetonate, nickel citrate and nickel formate and (B) at least one iron compound selected from the group consisting of Fe 3  C, Fe 2  (MoO 4 ) 3 , Fe 2  O 3 , Fe 3  O 4 , FeS, cyclopentadienyl iron dicarbonyl, ferric acetylacetonate, ferric hydroxy distearate, and ferrocene. Substantial smoke retardation is also obtained by including the above nickel compounds or iron compounds individually in the vinyl chloride or vinylidene chloride polymer compositions.

BACKGROUND OF THE INVENTION

Vinyl chloride and vinylidene chloride polymers are known to beself-extinguishing and relatively more flame retardant than otherpolymers such as polyethylene, polypropylene and the like. However, asubstantial amount of smoke may be produced upon exposure of vinylchloride and vinylidene chloride polymers to a flame. Conventional flameretardants such as antimony oxide do not aid in smoke reduction.

The following art is related to the present invention. Nickel oxides oriron oxides are effective in amounts up to several percent as condensingagents for polyvinyl halides (U.S. Pat No. 2,157,997). Fe₂ O₃ may beused together with other materials to flameproof polyvinyl chloride(U.S. Pat. No. 2,610,920). Fe₂ O₃ is a known smoke retardant in vinylchloride polymers (Neth. Pat. No. 7316-552). Other art teaching use ofiron oxides in PVC includes U.S. Pat. No. 2,902,460, 16 SPE J. 535 - 544(1962) (57 Chem. Abs. 8730c), Brit. 813,447 (53 Chem. Abs. 17578F), andBrit. 923,322 (59 Chem. Abs. 4125a). U.S. Pat. No. 3,577,346 teaches useof organoiron compounds in numerous polymers in order to impart coronaresistance. The fact that an additive is a flame retardant does not meanthat it will have good smoke retardant properties, as is well known tothose skilled in the art. New smoke retardant vinyl chloride andvinylidene chloride polymer compositions are desired.

SUMMARY OF THE INVENTION

Smoke retardant vinyl chloride and vinylidene chloride polymercompositions are obtained by including therein a synergistic mixture of(A) at least one nickel compound selected from the group consisting ofNiCO₃, NiCrO₄, NiI₂, NiO, NiS, NiSO₄, nickel acetylacetonate, nickelcitrate and nickel formate, and (B) at least one iron compound selectedfrom the group consisting of Fe₃ C, Fe₂ (MoO₄)₃, Fe₂ O₃, Fe₃ O₄, FeS,cyclopentadienyl iron dicarbonyl, ferric acetylacetonate, ferric hydroxydistearate and ferrocene. Substantial smoke retardation is also obtainedby including these iron compounds individually in the vinyl chloride orvinylidene chloride polymer compositions: Fe₃ C, Fe₂ (MoO₄)₃, FeS,cyclopentadienyl iron dicarbonyl, ferric acetylacetonate and ferrichydroxy distearate.

DETAILED DESCRIPTION

The following compounds are novel additives in vinyl chloride andvinylidene chloride polymer compositions and are effective individuallyas smoke retardants: Fe₃ C, Fe₂ (MoO₄)₃, FeS, cyclopentadienyl irondicarbonyl, ferric acetylacetonate and ferric hydroxy distearate.Moreover, the present invention also encompasses vinyl chloride andvinylidene chloride polymer compositions containing therein synergisticmixtures of (A) at least one nickel compound selected from the groupconsisting of NiCO₃, NiCrO₄, NiI₂, NiO, NiS, NiSO₄, nickelacetylacetonate, nickel citrate and nickel formate, and (B) at least oneiron compound selected from the group consisting of Fe₃ C, Fe₂ (MoO₄)₃,Fe₂ O₃, Fe₃ O₄, FeS, cyclopentadienyl iron dicarbonyl, ferricacetylacetonate, ferric hydroxy distearate and ferrocene.

Vinyl chloride and vinylidene chloride polymers used in this inventioninclude homopolymers, copolymers and blends of homopolymers and/orcopolymers. The vinyl chloride and vinylidene chloride polymers maycontain from 0 up to about 50% by weight of at least one othervinylidene monomer (i.e., a monomer containing at least one terminal CH₂= C< group per molecule) copolymerized therewith, more preferably up toabout 20% by weight of such monomer. These monomers include 1-olefinshaving from 2 to 12 carbon atoms, more preferably from 2 to 8 carbonatoms, such as ethylene, propylene, 1-butene, isobutylene 1-hexane,4-methyl-1-pentene and the like; dienes having from 4 to 10 carbon atomsincluding conjugated dienes as butadiene, isoprene, piperylene and thelike; ethylidene norbornene and dicyclopentadiene; vinyl esters andallyl esters such as vinyl acetate, vinyl chloroacetate, vinylpropionate, vinyl laurate, allyl acetate and the like; vinyl aromaticssuch as styrene, α-methyl styrene, chlorostyrene, vinyl toluene, vinylnaphthalene and the like; vinyl and allyl ethers and ketones such asvinyl methyl ether, allyl methyl ether, vinyl isobutyl ether, vinyln-butyl ether, vinyl chloroethyl ether, methyl vinyl ketone and thelike; vinyl nitriles such as acrylonitrile, methacrylonitrile and thelike; cyanoalkyl acrylates such as α-cyanomethyl acrylate, the α-, β-and γ-cyanopropyl acrylates and the like; olefinically unsaturatedcarboxylic acids and esters thereof, including α,β-olefinicallyunsaturated acids and esters thereof such as methyl acrylate, ethylacrylate, chloropropyl acrylate, butyl acrylate, hexyl acrylate,2-ethylhexyl acrylate, dodecyl acrylate, octadecyl acrylate, cyclohexylacrylate, phenyl acrylate, glycidyl acrylate, methoxyethyl acrylate,ethoxyethyl acrylate, hexylithioethyl acrylate, methyl methacrylate,ethyl methacrylate, butyl methacrylate, glycidyl methacrylate and thelike, and including esters of maleic and fumaric acid and the like;amides of the α,β-olefinically unsaturated carboxylic acids such asacrylamide and the like; divinyls, diacrylates and other polyfunctionalmonomers such as divinyl benzene, divinyl ether, diethylene glycoldiacrylate, ethylene glycol dimethacrylate, methylene-bis-acrylamide,allyl pentaerythritol, and the like; bis (β-haloalkyl) alkenylphosphonates such as bis(β-chloroethyl) vinyl phosphonate and the like;and the like.

More preferred monomers include 1-olefins having from 2 to 12 carbonatoms, more preferably from 2 to 8 carbon atoms, such as ethylene,propylene, 1-butene, isobutylene, 1-hexene, 4-methyl-1-pentene and thelike; vinyl esters and allyl esters such as vinyl acetate, vinylchloroacetate, vinyl propionate, vinyl laurate, allyl acetate and thelike; olefinically unsaturated carboxylic acids and esters thereof,including α,β-olefinically unsaturated acids and esters thereof such asmethyl acrylate, ethyl acrylate, chloropropyl acrylate, butyl acrylate,hexyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, octadecylacrylate, cyclohexyl acrylate, phenyl acrylate, glycidyl acrylate,methoxyethyl acrylate, ethoxyethyl acrylate, hexylthioacrylate, methylmethacrylate, ethyl methacrylate, butyl methacrylate, glycidylmethacrylate and the like, and including esters of maleic and fumaricacid and the like; and amides of α,β-olefinically unsaturated carboxylicacids such as acrylamide and the like.

More preferred smoke retardant synergistic mixtures include (A) at leastone nickel compound selected from the group consisting of NiCO₃, NiO,NiS, nickel acetylacetonate and nickel formate and (B) at least one ironcompound selected from the group consisting of Fe₂ O₃, Fe₃ O₄, Fe₂(MoO₄)₃ and ferric hydroxy distearate. More preferred individual smokeretardant additives include Fe₂ (MoO₄)₃, ferric acetylacetonate andferric hydroxy distearate. Supporting media such as Al₂ O₃, SiO₂ andother substantially inert inorganic supporting materials known in theart may be used for the smoke retardant additives and in many cases arepreferred, since additive surface area is greatly increased for smokereduction purposes.

Not all nickel compound/iron compound mixtures are synergistic, and itis difficult or impossible to predict synergism. Mixtures found to benonsynergistic include NiMoO₄.H₂ O and Fe₂ O₃, Ni₂ O₃ and Fe₂ O₃, Ni andfe₃ O₄, and Ni₃ (PO₄)₂ and ferrocene. Other nonsynergistic combinationsinclude Ni(BO₂)₂ and Fe₂ O₃, NiSnO₃ and Fe₂ O₃, and nickel stearate andFe₂ O₃. Thus, it was surprising and unexpected to find synergistic smokereduction using the specific nickel compound/iron compound mixtures ofthis invention.

The additive compounds used in this invention are polycrystalline oramorphous fine powders, preferably with an average particle size lessthan about 200 microns, more preferably from about 0.5 to about 150microns. Polymer compositions containing the additives may have colorssimilar to, although somewhat lighter than, the additives themselves.The additive compounds are used in total amounts from about 0.01 toabout 20 parts by weight per 100 parts by weight of polymer. Use of morethan about 20 parts by weight of additive per 100 parts by weight ofpolymer probably will affect adversely other important physicalproperties, such as tensile strength and the like.

The vinyl chloride and vinylidene chloride polymers may be prepared byany method known to the art such as by emulsion, suspension, bulk orsolution polymerization. The additive compounds may be mixed with thepolymer emulsion, suspension, solution or bulk mass before monomerrecovery and/or drying. More preferably the compounds may be mixed withdry granular or powdered vinyl halide polymers. The polymer and compoundmay be mixed thoroughly in granular or powder form in apparatus such asa Henschel mixer and the like. Alternatively, this step may beeliminated and the mixing done while the polymer mass is fluxed, fusedand masticated to homogeneity under fairly intensive shear in or on amixer apparatus having its metal surface in contact with the material.The fusion temperature and time will vary according to the polymercomposition and level of additive compound but will generally be in therange of about 300° to 400°F and 2 to 10 minutes.

Smoke retardancy may be measured using an NBS Smoke Chamber according toprocedures described by Gross et al., "Method for Measuring Smoke fromBurning Materials", Symposium of Fire Test Methods -- Restraint & Smoke1966, ASTM STP 422, pp. 166-204. Maximum smoke density (D_(m)) is ademensionless number and has the advantage of representing a smokedensity independent or chamber volume, specimen size or photometer pathlength, provided a consistent dimensional system is used. Maximum rateof smoke generation (R_(m)) is defined in units of min⁻. Percent smokereduction is calculated using this equation: ##EQU1## The term "D_(m)/gram" means maximum smoke density per gram of sample. D_(m) and otheraspects of the physical optics of light transmission through smoke arediscussed fully in the above ASTM publication.

Smoke retardance may be measured quickly using the Goodrich Smoke-CharTest. Test samples may be prepared by dry blending polymer resin andsmoke retardant additives. The blend is ground in a liquid N₂ -cooledgrinder to assure uniform dispersion of the smoke retardant additives inthe resin. Small (about 0.3 g) samples of the polymer blend are pressedinto pellets about one-fourth inch in diameter for testing.Alternatively, test samples may be prepared by blending resin, smokeretardant additives and lubricant(s) or processing aid(s) in a blendersuch as an Osterizer blender. The blend is milled, pressed into sheets,and cut into small (about 0.3 gram) samples for testing. The testsamples are placed on a screen and burned for 60 seconds with a propanegas flame rising vertically from beneath the sample. Sample geometry ata constant weight has been found not to be significant for the smallsamples used in this test. A Bernz-O-Matic pencil flame burner head isused with gas pressure maintained at 40 psig. The sample is immersedtotally and continuously in the flame. Smoke from the burning samplerises in a vertical chimney and passes through the light beam of a Model407 Precision Wideband Photometer (Grace Electronics, Inc., Cleveland,Ohio coupled with a photometer integrator. Smoke generation is measuredas integrated area per gram of sample.

The vinyl chloride and vinylidene chloride polymer compositions of thisinvention may contain the usual compounding ingredients known to the artsuch as fillers, stabilizers, opacifiers, lubricants, processing aids,impact modifying resins, plasticizers, antioxidants and the like.

The following examples illustrate the present invention more fully.

EXAMPLES 1 - 9

The following recipe was used:

    ______________________________________                                        MATERIAL                PARTS                                                 ______________________________________                                        Polyvinyl Chloride*     100.0                                                 Polyethylene Powder Processing Aid                                                                    1.5                                                   Additive (A)**          Variable                                              Additive (B)***         Variable                                              ______________________________________                                         *Homopolymer having an inherent viscosity of about 0.92-99; ASTM              classification GP-4-15443.                                                    **Nickel compound selected from the group consisting of NiCO.sub.3,           NiCrO.sub.4, NiI.sub.2, NiO, NiS, NiSO.sub. 4, nickel acetylacetonate,        nickel citrate and nickel formate. The control sample contained no            additive.                                                                     ***Iron compound selected from the group consisting of Fe.sub.3 C,            Fe.sub.2 (MoO.sub.4).sub.3, Fe.sub.2 O.sub.3, Fe.sub.3 O.sub.4, FeS,          cyclopentadienyl iron dicarbonyl, ferric acetylacetonate, ferric hydroxy      distearate and ferrocene. The cyclopentadienyl iron dicarbonyl was            supported on Al.sub.2 O.sub.3 (0.2 g. cyclopentadienyl iron dicarbonyl        supported on 20 g. Al.sub.2 O.sub.3 having a 220 m.sup.2 /g surface area)     The control sample contained no additive.                                

Each experimental sample was prepared by milling the recipe materials ona two-roll mill for about 5 minutes at a roll surface temperature ofabout 320°F. The milled samples were pressed into 6 in. × 6 in. × 0.050in. sheets with the exception of Example 2, where a 6 in. × 6 in × 0.075inc. sheet was used. Pressing was done at about 310° - 320°F using40,000 lbs. of force applied to a 4-in. ram. The samples were given a 2minute preheat prior to pressing for 8 minutes under full load.

The molded samples were cut into 3 in. × 3 in. × 0.050 in. sections withthe exception of Example 2, where a 3 in. × 3 in. × 0.075 in. sectionwas used. Testing was performed using the flaming mode of the NBS SmokeChamber Test (ASTM STP 422, pp. 166-204) described heretofore. Testresults are given in Table I.

                                      TABLE I                                     __________________________________________________________________________                              Maximum  Maximum Smoke                                                        Rate of Smoke                                                                          Density per                                                                            Smoke                                  Additive (A)                                                                           Additive (B)                                                                              Generation                                                                             Gram of Sample                                                                         Reduction                         Example                                                                            (phr)    (phr)       R.sub.m, min.sup..sup.-1)                                                              (D.sub.m /g)                                                                           (%)                               __________________________________________________________________________    Control                                                                            (No Additive)                                                                          (No Additive)                                                                             556      68.6     --                                1    NiI.sub.2 (5)                                                                          --          191      35.9     47.7                                   --       Fe.sub.3 C (5)                                                                            263      36.9     46.2                                   NiI.sub.2 (4)                                                                          Fe.sub.3 C (1)                                                                            161      25.1     63.4                              2*   NiO (5)**                                                                              --          198      43.0     37.3                                   --       Fe.sub.2 O.sub.3 (5)                                                                      297      18.4     73.2                                   NiO (4)  Fe.sub.2 O.sub.3 (1)                                                                      237      14.4     79.0                              3    NiO (6)  --          169      43.4     36.7                                   --       Fe.sub.2 O.sub.3 (6)                                                                      300      20.4     70.3                                   NiO (5)  Fe.sub.2 O.sub.3 (1)                                                                      229      12.6     81.6                                   NiO (3)  Fe.sub.2 O.sub.3 (3)                                                                      271      16.5     76.0                              4*** NiO (6)  --          169      43.4     36.7                                   --       Cyclopentadienyl iron                                                                     328      43.9     36.0                                            dicarbonyl (6)                                                       NiO (5)  Cyclopentadienyl iron                                                                     171      38.8     43.4                                            dicarbonyl (1)                                                       NiO (3)  Cyclopentadienyl iron                                                                     306      40.7     40.7                                            dicarbonyl (3)                                                  5    NiO (5)  --          247      48.9     28.7                                   --       Fe.sub.3 O.sub.4 (5)                                                                      208      20.2     70.6                                   NiO (4)  Fe.sub.3 O.sub.4 (1)                                                                      309      18.2     73.5                              6    NiO (6)  --          169      43.4     36.7                                   --       Fe.sub.2 (MoO.sub.4).sub.3 (6)                                                            371      22.5     67.2                                   NiO (3)  Fe.sub.2 (MoO.sub.4).sub.3 (3)                                                            173      13.5     80.3                              7    Nickel Citrate (5)                                                                     --          244      57.2     16.6                                   --       Ferric acetylace-                                                                         170      25.2     63.3                                            tonate (5)                                                           Nickel Citrate                                                                         Ferric acetylace-                                                                         121      23.4     65.9                                   (4)      tonate (1)                                                      8    NiO (5)  --          247      48.9     28.7                                   --       Ferric hydroxy di-                                                                        346      33.4     51.3                                            stearate (5)                                                         NiO (4)  Ferric hydroxy di-                                                                        343      22.5     67.2                                            stearate (1)                                                    9    NiSO.sub.4 (5)                                                                         --          174      51.9     24.3                                   --       FeS (5)     305      36.0     47.5                                   NiSO.sub.4 (4)                                                                         FeS (1)     220      34.5     49.7                                   NiSO.sub.4 (3)                                                                         FeS (2)     205      32.4     52.8                              __________________________________________________________________________     *Sample size was 3 in. × 3 in. × 0.075 in.                        **Sample with NiO alone also contained 1 part polyethylene instead of 1.5     parts                                                                         ***0.2 g. cyclopentadienyl iron dicarbonyl supported on 20 g. Al.sub.2        O.sub.3 having a 220 m.sup.2 /g surface area.                            

The above results demonstrate that the additive mixtures used in thisinvention are synergistic and substantially retard smoke formationduring burning of rigid polyvinyl chloride in the NBS Smoke Chamber(ASTM STP 422, pp. 166-204). The results also demonstrate the smokeretardant effects of individual additives in the same test.

EXAMPLES 10 - 17

The following recipe was used:

    ______________________________________                                        MATERIAL           PARTS                                                      ______________________________________                                        Polyvinyl Chloride*                                                                              100.0                                                      Additive (A)**     Variable                                                   Additive (B)***    Variable                                                   ______________________________________                                         *Homopolymer having an inherent viscosity of about 0.92 - 0.99; ASTM          classification GP-4-15443.                                                    **Nickel compound selected from the group consisting of NiCO.sub.3,           NiCrO.sub. 4, NiI.sub. 2, NiO, NiS, NiSO.sub. 4, nickel acetylacetonate,      nickel citrate and nickel formate.                                            ***Iron compound selected from the group consisting of Fe.sub.3 C,            Fe.sub.2 (MoO.sub.4).sub.3 , Fe.sub. 2 O.sub. 3, Fe.sub.3 O.sub. 4, FeS,      cyclopentadienyl iron dicarbonyl, ferric acetylacetonate, ferric hydroxy      distearate and ferrocene.                                                

Each experimental sample was prepared by blending resins and additivesin a liquid N₂ -cooled grinder to assure uniform dispersion of the smokeretardant additives in the resin. Small (about 0.3 gram) samples of thepolymer blend were pressed into pellets about one-fourth inch indiameter and tested using the Goodrich Smoke-Char Test describedheretofore. Test results are given in Table II.

                                      TABLE II                                    __________________________________________________________________________         Additive (A)                                                                              Additive (B)                                                                           Smoke Formation per                                 Example                                                                              (phr)       (phr)  Gram of Sample                                                                            Smoke Reduction (%)                     __________________________________________________________________________    Control                                                                            None        None     67.4        --                                       10  NiCO.sub.3 (5)                                                                              --     38.9        42.3                                           --        Fe.sub.2 O.sub. 3 (5)                                                                  32.8        51.3                                         NiCO.sub.3 (4)                                                                            Fe.sub.2 O.sub. 3 (1)                                                                  11.5        82.9                                     11  NiCrO.sub.4 (5)                                                                             --     40.0        40.7                                           --        Fe.sub.2 O.sub.3 (5)                                                                   32.8        51.3                                         NiCrO.sub. 4 (4)                                                                          Fe.sub.2 O.sub. 3 (1)                                                                  26.3        61.0                                     12  NiO (2)       --     60.7         9.9                                           --        Fe.sub.2 O.sub. 3 (2)                                                                  24.9        63.1                                         NiO (1)     Fe.sub.2 O.sub. 3 (1)                                                                  17.6        73.9                                     13  NiO (5)       --     32.0        52.5                                           --        Fe.sub.2 O.sub. 3 (5)                                                                  32.8        51.3                                         NiO (4)     Fe.sub.2 O.sub.3 (1)                                                                    8.8        86.9                                     14  NiS (5)       --     58.7        12.9                                           --        Fe.sub.2 O.sub. 3 (5)                                                                  32.8        51.3                                         NiS (4)     Fe.sub.2 O.sub. 3 (1)                                                                  17.7        73.7                                     15  Nickel Acetylaceton-                                                          ate (5)       --     37.8        43.9                                           --        Fe.sub.2 O.sub. 3 (5)                                                                  32.8        51.3                                         Nickel Acetylaceton-                                                          ate (4)     Fe.sub.2 O.sub. 3 (1)                                                                  14.9        77.9                                     16  Nickel Formate (5)                                                                          --     49.3        26.8                                           --        Fe.sub.2 O.sub. 3 (5)                                                                  32.8        51.3                                         Nickel Formate (4)                                                                        Fe.sub.2 O.sub. 3 (1)                                                                  17.8        73.6                                     17  NiO (5)       --     29.3        56.5                                           --        Ferrocene (5)                                                                          45.3        32.8                                         NiO (4)     Ferrocene (1)                                                                          24.3        64.0                                    __________________________________________________________________________

These results demonstrate that the defined additives substantiallyreduce smoke evolution during forced burning of rigid polyvinyl chloridein the Goodrich Smoke-Char Test. The results also demonstrate the smokeretardant effects of individual additives in the same test.

The improved smoke retardant vinyl chloride and vinylidene chloridepolymer compositions of this invention are useful wherever smokeresistance is desirable, such as in carpets, house siding, plasticcomponents for airplane interiors, and the like. Of course, overallsuitability for a particular use will depend upon other factors as well,such as comonomer type and level, compounding ingredient type and level,polymer particle size, etc.

I claim:
 1. A smoke retardant composition comprising a vinyl chloride orvinylidene chloride polymer together with (A) at least one nickelcompound selected from the group consisting of NiCO₃, NiCrO₄, NiI₂, NiO,NiS, NiSO₄, nickel acetylacetonate, nickel citrate and nickel formateand (B) at least one iron compound selected from the group consisting ofFe₃ C, Fe.sub. 2 (MoO₄)₃, Fe₂ O₃, Fe₃ O₄, FeS, cyclopentadienyl irondicarbonyl, ferric acetylacetonate, ferric hydroxy distearate anddicyclopentadienyl iron, said compounds (A) and (B) being present in atotal amount from about 0.25 to about 20 weight parts per 100 weightparts of polymer.
 2. A composition of claim 1 wherein said polymercontains copolymerized therewith up to about 50% by weight of at leastone other vinylidene monomer containing at least one terminal CH₂ =C<group per molecule.
 3. A composition of claim 2 wherein said polymercontains copolymerized therewith up to about 20% by weight of said othervinylidene monomer.
 4. A composition of claim 3 wherein said othervinylidene monomer is selected from the group consisting of 1-olefinshaving from 2 to 12 carbons atoms, vinyl esters, α,β-olefinicallyunsaturated carboxylic acids and esters thereof, amides ofα,β-olefinically unsaturated carboxylic acids, and esters of fumaric andmaleic acid.
 5. A composition of claim 4 wherein said compound has anaverage particle size less than about 200 microns.
 6. A composition ofclaim 5 wherein said compound (A) is NiI₂ and said compound (B) is Fe₃C.
 7. A composition of claim 5 wherein said compound (A) is NiO and saidcompound (B) is Fe₂ O₃.
 8. A composition of claim 5 wherein saidcompound (A) is NiO and said compound (B) is cyclopentadienyl irondicarbonyl.
 9. A composition of claim 5 wherein said compound (A) is NiOand said compound (B) is Fe₃ O₄.
 10. A composition of claim 5 whereinsaid compound (A) is NiO and said compound (B) is Fe₂ (MoO₄)₃.
 11. Acomposition of claim 5 wherein said compound (A) is nickel citrate andsaid compound (B) is ferric hydroxy distearate.
 12. A composition ofclaim 5 wherein said compound (A) is NiSO₄ and said compound (B) is FeS.13. A composition of claim 5 wherein said compound (A) is NiCO₃ and saidcompound (B) is Fe₂ O₃.
 14. A composition of claim 5 wherein saidcompound (A) is NiCrO₄ and said compound (B) is Fe₂ 0₃.
 15. Acomposition of claim 5 wherein said compound (A) is NiS and saidcompound (B) is Fe₂ O₃.
 16. A composition of claim 5 wherein saidcompound (A) is nickel acetylacetonate and said compound (B) is Fe₂ O₃.17. A composition of claim 5 wherein said compound (A) is nickel formateand said compound (B) is Fe₂ O₃.
 18. A composition of claim 5 whereinsaid compound (A) is NiO and said compound (B) is dicyclopentadienyliron.